Feed water pump



Aug. 11, 1959 A. CILARKSON ET AL FEED WATER PUMP 4 Sheets-Sheet 1 Filed Dec. 21, 1956 INVENTORS. ALICK CLARKSON BY WILLIAM W- PAR KS ug 1959 A. CLARKSON ETAL 2,

FEED WATER PUMP 4 Sheets-Shet 2 Filed Dec. 21, 1956 JNVENTORS. ALICK CLARKSON wlLLlAM vv. PARKS 1959 A. CLARKSON EIALI 2,899,247

Y FEED WATER PUMP Filed Dec. 21, 1956 4 Sheets-Sheet 5 INVENTORS. AUCK CLARKSON W\\ L\AM.\M PARKS Aug. 1959 A. CLARKSON ETAL 2,899,247

FEED WATER PUMP 4 Sheets-Sheet 4 Filed Dec. 21, 1956 INVENTORS. ALICK CLARKSON WlLLiAM W- PARKS vBY United States Patent 9 FEED WATER "PUMP ,Alick "Clarkson, Paul Spur, .Ariz., and William W. Parks, Chicago, IlL, assignors to Vapor Heating Corporation, Chicago, BL, a corporation of Delaware Application December 21, 1956, Serial No-629fi64 8 Claims. (Cl. 309-2 The improved pump construction comprising the present invention has been designed primarily for use as a water feed pump in connection with boiler or steam generator installations wherein hot replacement water is fed to the boiler, either as raw water or water which has beenseparated from steam and returned to the -boil,er,.or as a combination of both.

Heretofore, considerable difficulty has been experienced, in water feed pumps of the multiple piston type herein shown, of maintaining the pump pistons properly aligned in their cylinders so as to prevent undue wear of the pistons and cylinder walls, when pistons having 'labyrinth sealing grooves were used, and to prevent undue wear of the packing rings when packed pistons were used. In somepinstances said misalignment has resulted from inaccurate assembly of the cylinders and valve chamber castings on ,the'base portion of the pump ,s tru ctur e. For

example, unequal tension of the bolts for cla'mping the above elements to the baseportion of the pump,or any undue torsion imposed on'the inlet and outlet. conduit connections therewith tend to shift the parts of the pump sufficiently to move the centers of the piston cylinders out of alignment with respect to the centers oflhe piston elements and thereby permit the hot fiuid (water or oil being handled by the pump to be forced between the pistons and the walls of the pump cylinders. Suchleakage reduces the pumping pressure and also results in rapid wear on the sealing surfaces. This wear is especially pronounced if packed pistons are used, since the temperatures and pressures, results in rapid deterioration of the packing. Similar results are also brought about by the normal difierential in thermal expansion and contraction of the relatively hot cylinder head casting of :the pump structure in relation to the 'base. portion. to which the headcasting and cylinders are clamped. I

The said misalignment may assume the form of slight tilting of the piston relative to the cylinder wall, in .Which I event with conventional forms of pistonassemblies the leakage of fluid past the pistons is always present when such thermal expansion takes place.

The present invention is designed to .overcome the above-noted limitations that are attendant upon the use pjf conventional piston assemblies and, toward this end it contemplates the provision of a novel form of piston assembly wherein the operative sealing portions of the assembly may shift laterally on the end of theplungeror piston rod on which the pistonassembly is mountedto accommodate limited late al di p e e o t e cy inde associated therewith and at the same time maintain .a highly efiicient seal between the piston assembly and the cylinder in which it is movably fitted.

The provision of a piston assembly of the character briefly outlined above being among the :principal objects of the invention, another object thereof isto provide :a packing assembly which is capable ofeasy removal from the end of the piston rod while the pumpis assembled so that the piston maybe .repackedand reinstalled .in-the pump assembly without necessitatingf long periods .of shutdown for complete pump overhaul.

It is a further object, in a reciprocating .pumpstr ucture, to providea piston assembly ofthissortwhere'in .thepacking .employed is self-adjusting and self-aligning .to -compensate for both normal wear and thermal expansiontand consequent displacement of the various operative .purnp parts.

Numerous other objects .and advantages of the invention not at this time enumerated will becomemore readily apparent .as thenature of the invention is better under- ..stood.

In .the accompanying drawings .forminga part of this specification, .a preferred embodiment of the invention has been shown.

In these drawings:

Fig. 1 a top plan view of a pump-construction constructed and assembledaccording to the principles of-the present invention; i

Fig. 2 is a sectional viewtaken substantially along the .line 2-2 of Fig. 1;- a

Fig. .3 is .an end .elevational view of the structure shown in Fig. l;

Fig.4 isa fragmentary enlarged :detail sectional view taken substantially along line 4-4 of Fig. :3'-through"the several piston constructions employed fin-connection with the invention; and l 1 1 .Fig. 5 is :a :further enlarged fragmentary-sectional 'view through one piston, the view being taken substantially along the line 5- 5 of Fig. 4.

Referring -now to the drawings'indetail and in particu- ,lar .tozFigs. .1 to ,5 inclusive. The pump constructionherein ,shownis of a reciprocal piston and cylinder "type and is shown as having associated therewith three piston and :cylinder assemblies although a greater orilesser number of such assemblies maybe employed if'desird. The pump construction involves in its general organization two main castings including a'crankcase casting 10*providing a chamber .12 within which -:thc're"is operatively mounted the crank shaft and connecting rod assembly as will be-described presently, and axvalve castingi14 -:pro'- viding a multiple valvecham-ber' 16. Disposed between the two castings .10 and 14am a'plurality of cylinders 18, three being shown in the present instance, which are clamped between the castings 10 and 14 and constitute the sole means whereby the castings are maintained in their spaced relationship, all in a manner that will like- .wise bemadeclear presently. 1

The three cylinders :18 are arranged in parallelism with one another and each is axially aligned with the castings 1-0 and '14 between which *itis interposed. The entire pump assembly may :be supported in any desired position of orientation, as for example vertically with the castings 10 and 14 superimposed so that the axes of the cylinders 18 are vertical or, as illustrated herein, hori'zontallyflwith the axes of the cylinders 18 extending horizontally. To facilitate such rhorizontal mounting of the assembly, a web structure 20 formed on the casting ll 0 affords a pair of spaced foot portions 22 which may be secured by means of studs 28 to a suitable "horizontal supporting plate 24. "The right hand end ofthe' casting 10 '(whioh may be regarded :herein as the rearlend of the pump assembly) is formed with a series of three spaced depending boss-like thickened portions v26 providing additional foot portions which may :be secured to the plate 24by studs 28.

The crankcase casting 10 is provided with a rear end closure plate or pan 30 which .is removably secured thereto by means .of studs 32. :It is also provided with a filling plug 34 .for lubricating oil, and a drain cook 36 in the usualmanner .of construction of crankcase assemblies."

Extending across "thereof and rotatably journalled in bearing plates 46 on opposite sides of the crankcase is a crank shaft 48 one end of which carries a ring gear 50 which meshes with 'as merging with flat parallel side walls, as shown best in Fig. 2 at 44. V

the crankcase chamber 12 transversely a smaller gear 52 mounted on a drive shaft 54. The shaft 54 extends across the crankcase and is rotatably ljournalled in the bearing plates 46 and has one end thereof projecting outwardly of the casing as at 56 for connection to a suitable driving motor (not shown). The crankshaft is provided with three eccentrically disposed bearing portions 58 which preferably assume 120 cir- 'cumferentially spaced positions around the axis of the shaft 48 and which cooperate with connecting rod assemblies 60, each including the usual connecting rod proper 62, bearing cap 64, wrist pin bearing 66 and "wrist pin 68. The crankcase casting 10 is formed with an internal axially extending crosshead guideor sheath 70, in which there are reciprocably disposed a series of cross head assemblies 72, each of which is pivotally connected to one of the connecting rods proper 62 through the medium of its respective wrist pin 68, as well as being connected to the rear or right hand end of a piston rod or plunger 74.

Each plunger 74 projects through the thickened end wall 42 of the casting 10 and is sealed therein by a packing gland .76. The front or left hand end'of each piston rod 74, as viewed in Fig. 2, has mounted thereon a composite floating piston assembly 78 the details -of which will be set forth subsequently and which, to -a large extent, embodies the novel structures which establish, in the present invention a new co-active relation of the pistons with the cylinders 18 and the piston 'rods 74. Each piston assembly 78 is operatively disposed and reciprocable within one of the cylinders 18.

Still referring to Figs. 1 to inclusive, the various cylinders 18 are formed of a suitable ceramic material such as porcelain, aluminum oxide or the like and each is in the form of a thick-walled, open-ended cylindrical member, the open rims of which are bevelled internally .as at 80 and the rear rim of which is centered within an .adaptor ring 82 seated within an annular recess 84 formed in the end wall 42 of the casting exteriorly thereof. The extreme end of the cylinder seats against a gasket 86 WhlCh is compressed thereby within the recess .84. The .forward open rim of each cylinder 18 is similarly seated within a recess 88 formed in the valve casting 14 and against a gasket 90 so that when the valve casting and crankcase casting 10 and 14 respectively are drawn together under the influence of certain clamp- 1ng means about to be described in detail, the various cylinders will be effectively sealed at their ends to the two castings.

As best seen in Figs. 3 and 4, the valve chamber 16 is divided by a pair of medial chamber walls 92 into three pump chambers 94, one for each cylinder 18 and in communication therewith. The three pump chambers 94 are in communication with a common transverse inlet manifold passage 96 formed in the casting 14 adjacent the bottom thereof and having an inlet opening 98 by means of which the passage may be operatively connected to the source of fluid undergoing pumping, as for example through a conduit 100. The chambers 94 are also in communication with a transverse discharge manifold passage 102 adjacent the top of the casting 14 and having an outlet opening 103 which may be operatively connected to a discharge conduit 104.

The valve casting 14 is formed with a generally rectangular apron 106 (Figs. 2 and 4) which encompasses the three cylinders 18 and the casting 14 is maintained in its position on the cylinders 18 as previously described by means of a series of relatively long clamping studs 108 (Figs. 1 and 3) of which there are six in number, and two somewhat shorter clamping studs 110. The various studs 108 and 110 extend completely through the casting 14 and are threadedly received in sockets 112 provided for them in the end wall 42 of the casting 10. The studs 108 are provided with clamping nuts 118 thereon by means of which the two castings 10 and 14 may be drawn toward each other and thus clamp the three cylinders 18 therebetween in sealing relationship as previously described. The two studs 110 are provided with clamping nuts 116 at the ends thereof which serve a similar purpose. The studs 108 are further formed with threaded extensions which project through the ends of a series of clamping bars 120 having medial web portions 122 adapted to bear against respective cylinder head members 124 and clamp the latter in' position against the valve casting 14 to close the various pump chambers 94 thereof.

Each cylinder head member 124 is generally in the form of a cylindrical plug having an annular seating flange 126 adapted to seat on a gasket 128 disposed within a shallow recess 130 communicating with the outer end of each pump chamber 94. The medial regions of each member 124 is formed with an annular recess v130 in which there are disposed a pair of resilient O-rings 132 which serve as buffer elements in connection with certain valve elements associated with the discharge passage 102 and the nature and function of which will now be made clear.

Referring now to Fig. 2:- The inlet manifold passage 96 communicates through a series of three valve ports 134 with the respective pump chambers 94, each port being fitted with a cage-like valve seat insert 136 designed for cooperation with a valve element 138 in the form of a spherical ball which is disposed in the adjacent pump chamber and is interposed between the valve seat insert 136 and the buffer elements 132 carried on the adjacent cylinder head member 124. An access opening 140 fitted with a closure plug 142 is formed in the casting 14 in transverse alignment with each inlet port 134 to facilitate removal or replacement of the valve seat insert 136 or valve element 138.

The outlet manifold passage 102 similarly communicates with the respective chambers 94 through a series of three valve ports 144 and these ports are fitted with valve seat inserts 146 designed for cooperation with valve elements 148 in the form of spherical balls. The valve elements are interposed between the valve seats 146 and resilient cushioning means 150 which may be in the form of yieldable cushioning pads carried at the inner ends of a series of valve cover elements 152 which fit within access openings 154 formed in the casting 14 and are sealed therein by gaskets 156. The valve cover elements 152 are held in position over their respective openings 154 by means of clamping bars 158 similar to the bars 120 and similarly held in position against the valve cover elements 152 by clamping studs 160. The various valve elements 138 and 148 are free floating members and they operate 'to cover or uncover their respective ports under the influence of the movements of the respective piston assemblies 78 as will be described in detail presently.

Referring now to Figs. 2 and 5: Each of the novel floating piston assemblies 78 on the end of its respective plunger .74 involves in its general organization a seating ring 162 which surrounds a reduced end 164 formed on the plunger and which seats against a shoulder 166. The ring 162 is formed with an annular groove 163 in the forwardface thereof in which there is disposed a sealing member which may be in the form of a resilient O- ring. The ring 162 is held against its seat on the shoulder 16 6 bymea ns"of an elongated hollow nut or clamping sleeve 172 which is threadedly received as at 174 on the reduced end 164 of the plunger 74 and the rear end of "Wliich sleeve bears against the ring'1'62. Surrounding the sleeve -172 and looselydisposed thereon is a piston head "including tubular packing retainer 176 having an enlarged retaining flange 178 formed on the rear end thereof and provided with a trough-shaped annular-groove 180 therein in which there is seated the rear-most packing element of a series of nested V-ring or Chevron packing elements 182 which surround the reduced portion of the piston head 176 and are adapted to bear inwardly against the same and outwardly against the inner wall of the cylinder 18 in sealing relationship with respect thereto. "The resilience of a spring 188 serves to take up any wear or compression of the packing rings and therefore insures a tight sealing fit of the packing rings against the cylindrical inner walls of the several cylinders. A tubular spring retainer 184 having a seating shoulder 186 formed thereon surrounds the clamping sleeve 172 and a spring 188 surrounds the retainer and bears at one end against the shoulder 186 and at its other end against a metal packing adaptor 190 which, in turn, bears against the foremost packing ring or element 182 in the series thereof in spreading relationship with respect thereto.

Disregarding for the moment the specific operation of the novel piston assemblies just described, the pump assembly disclosed herein operates generally in the manner of reciprocating pump structures of the same general character by the alternate application of above-normal or sub-normal pressures to the various pump chambers 94 in accordance with the longitudinal reciprocal travel of the piston assemblies 78 in their respective cylinders 18. On the pressure stroke of each piston assembly 78, the inlet valve element 138 (Fig. 2) is forced against its seat 136 while the outlet valve element 148 is forced from its seat 146 so that fluid may be expelled from the pump chamber 94 and into the discharge manifold passage 102. Conversely, on the suction stroke of each piston assembly, the outlet valve element 148 is drawn against its seat while the inlet valve element 138 is drawn from its seat so that the fluid will be taken into the pump chamber 94. Insofar as the piston assemblies 78 are concerned, these floating assemblies serve to compensate for any misalignment of the cylinder 18 relative to the plungers 74 which may result from improper assembly of the several parts and which may also result from any unequally distributed thermal expansion in the two main pump castings and 14, as well as for any unequal thermal expansion which may take place in either casting individually under the influence of localized or overall temperature changes in the pump structure. For example, in the assembly of the pump structure when the parts are cold, the clamping bolts 108 and 110 are tightened into the casting 10 in the manner previously described to clamp the casting 14 against the left hand end of the various cylinders 18 as viewed in Figs. 1 and 2 and thus clamp the other end of the cylinders against the block 10. Thereafter the nuts 118 are applied and tightened on the bolts 108 to clamp the cylinder head members 124 in position. When the pump is set into operation for the pumping of hot liquids, as for example, boiler feed water, thermal expansion will take place in the various parts of the pump structure including the two castings 10 and 14. Since the casting 14 is in close proximity to the hot fluid undergoing pumping, the extent of such thermal expansion will be greater in this casting than in the casting 10 and, depending upon the manner of initial tightening of the bolts 108 and 11d, certain of these bolts will serve as reaction members while others thereof will yield to the reaction forces involved with the net results that there will be relative lateral displacement of the cylinders 18 with respect to each other as well as with respect to the axes of their respective plungers or piston rods 74. To assimilate this relative displacement of parts, the tubular retainer 176 and packing 182 carried thereby will follow the lateral movements of the cylinder walls within which they are confined and the retainer 176 will shift grooves laterallyon the plunger 74 and seating ring 162 while at the same time rthe sealing element or O-ring will maintain its seal between the retainer and seating ring regardless of any angular misalignment between the cylinder 18 and piston rod 84. It will be understood, .of course, that neither the sub-normal pressures involved in the various pump chambers 94, nor the compressional forces involved in the crankcase chamber 12 will be sufficiently great as to cause the piston head 178 to move out of contact with the sealing element'170 and the spring 188 is designed so as to have suflicient strength to overcome any tendency for these elements to become so separated.

In compliance with Title 35, US. Code, Section 22, a preferred embodiment of the invention has been shown in the accompanying drawings and described herein. While the preferred embodiment is a packed piston type of pump, certain of the features of the invention are-applicable to piston assemblies having labyrinth sealing Therefore, it should be understood that theinvention is not limited to the specific construction shown in the absence-of specific limitations in the claims.

We claim:

1. In combination with a pump cylinder and an axially reciprocating piston rod projecting into the cylinder, a piston assembly mounted on the free end of said piston rod and including a seating ring fixedly secured to the rod, a piston head having a sealed engagement with the inner wall of the cylinder and loosely disposed on said piston rod for limited lateral displacement thereon, and sealing means interposed between said seating ring and piston head.

2. In combination with a plurality of pump cylinders and axially reciprocable piston rods projecting into the cylinders, piston assemblies mounted on the free end of each piston rod and including in each case a seating ring member fixedly secured to a piston rod and presenting a flat annular radial sealing surface, a piston head having a sealed movable engagement with the inner wall of an associated cylinder and loosely disposed on its associated piston rod for limited lateral displacement thereon to compensate for displacement of one cylinder relative to another, said piston head presenting a flat annular radial sealing surface in opposition to said sealing surface on the seating ring member, and means interposed between said sealing surfaces for preventing the flow of fluid radially along said surfaces.

3. In combination with a pump cylinder and an axially reciproca ble piston rod projecting into the cylinder, 2. piston assembly mounted on the free end of said piston rod and including a seating ring fixedly secured to the rod, a tubular packing retainer surrounding said piston rod and loosely disposed thereon for limited lateral displacement and angular misalignment thereon, a resilient packing material surrounding said retainer and compressed between the latter and the inner Wall of the cylinder in sealing relation with respect to said retainer and wall, and sealing means interposed between said seating ring and retainer.

4. In combination with a pump including a plurality of cylinders and an axially reciprocable piston rod projecting into each cylinder, a piston assembly mounted on the free end of each piston rod with capacity for lateral movement thereon to compensate for displacement of one cylinder relative to another, each piston assembly including a seating ring member fixedly secured to its associated piston rod and presenting a flat annular radial sealing surface, a tubular packing retainer member surrounding said piston rod and loosely disposed thereon to provide said lateral movement, each said retainer member presenting a flat annular radial sealing surface in opposition to said sealing surface on its associated seating ring member, means interposed between said sealing surfaces for preventing the flow of fluid radially along said surfaces, and a soft resilient packing material surrounding said retainer member and compressed between the latter and the inner wall of the cylinder in sealing relation with respect'to the retainer. member and wall.

' 5. The.combination set forth in claim 4 wherein said flow-preventing means for each piston assembly comprises an annular groove formed in the sealing surface on one of said members and compressible means disposed in said groove and bearing against the sealing surfaces of both of said members.

6. The combination set forth in claim 5 wherein the groove is formed in the sealing surface provided on said seating member.

7. In combination with a plurality of pump cylinders and an axially reciprocable piston rod projecting into each cylinder, a separate piston assembly mounted on the free end of each piston rod and including in each case a seating ring fixedly secured to an associated piston rod and presenting a flat annular radial sealing surface, a tubular packing retainer surrounding an associated piston rod and loosely disposed thereon for limited lateral displacement and angular misalignment thereon, each said retainer presenting a flat annular radial sealing surface in opposition to the sealing surface on the seating ring,

means interposed between said sealing surfaces for preventing the flow of fluid radially along said surfaces, a soft resilient packing material surrounding each retainer and compressed between the latter and the inner wall of its associated cylinder in sealing relation with respect to the retainer and wall, said packing retainer being formed with a radial flange thereon providing an annular seating shoulder for said packing material, means carried by said piston rod providing a second shoulder spaced from said first shoulder and opposed thereto, and a compression spring interposed between said shoulders and bearing at one end against said packing material for compressing the same against said seating shoulder.

8. The combination set forth in claim 7 wherein said seating shoulder is formed with an annular trough therearound in which said packing material is seated under the influence of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,808 Christensen Nov. 12, 1946 2,449,657 Kishline Sept. 21, 1948 2,604,048 Wahlmark July 22, 1952 

